1.,Boil the pasta until al dente, according to package directions.,Drain and rinse with cool water to stop the cooking.,When drained, place in your 3-quart casserole dish and set aside.,2.,While pasta is cooking, start your bacon by cutting into strips.,Add to a large frying pan and cook, stirring over medium high heat.,When starting to brown, add chopped onion, stir and cook until onions become browned and caramelized.,3.,Add ground beef to the same frying pan and cook until crumbled and browned.,Remove from heat, stir into noodles and set aside.,4.,Preheat the oven to 375 degrees.,5.,Over medium heat, melt the butter in a medium sauce pan.,6.,Add the flour, sea salt, dry mustard, pepper, and paprika.,Stir constantly over medium heat for about three minutes.,7.,Slowly add in the milk while whisking.,8.,Keeping on medium heat, whisk constantly for about 10 minutes, until the sauce thickens and will coat the back of a spoon.,9.,Remove from heat, and stir in 2 1/2 cups of the cheese, stirring until melted.,10.,Pour the cheese sauce over the noodles and stir until combined.,11.,Sprinkle on the rest of the cheese and chives.,______,12.,Bake for about 25-30 minutes, until it gets golden brown, bubbly and ooey-gooey!,13.,Serve quick before it disappears.,There were no leftovers to put away when I made this!